Many factors such as grass type, cut height, water content of the leaf, moisture content of the ground, air temperature and humidity, etc. have an impact on this quality of the ball roll. Furthermore, all of these factors can change from hole to hole and over the course of a few minutes. For a golfer, understanding this measurement is critical to accurate putting as it is a primary factor in determining the strength of a desired putting stroke.
Many mechanical systems have been used in the past, each with significant limitations or flaws. The most common method rolls a ball down a portable ramp onto the green and this rollout distance is measured. This is done in several different directions to account for any slope in the green and the numbers are combined to compute a “green speed”. This method is very inconvenient for a golfer to user, it is prone to errors if used improperly and it cannot be used at all in areas with steep grades to the green.